Joshua 6:4-6

4And seven priests shall bear before the ark seven trumpets of rams’ horns: and the seventh day ye shall compass the city seven times, and the priests shall blow with the trumpets. 5And it shall come to pass, that when they make a long blast with the ram’s horn, and when ye hear the sound of the trumpet, all the people shall shout with a great shout; and the wall of the city shall fall down flat, and the people shall ascend up every man straight before him.1

6And Joshua the son of Nun called the priests, and said unto them, Take up the ark of the covenant, and let seven priests bear seven trumpets of rams’ horns before the ark of Yhwh.